The Sapphire Radeon HD 6850 graphics card is right up our street. You see, here at PC Advisor, we love true value graphics cards, products that deliver significant amounts of firepower and, in the process, surpass other products that cost some £25 or even £50 more.
Until recently, the nVidia GeForce GTX 460 has been very much in that bracket since its review in September. Then ATI came up with a worthy response, unveiling its new mid-range Radeon HD 6870 and Radeon HD 6850 cards. We were very much impressed with the HD 6870's performance, but a significant cut in the cost of nVidia's GTX 460 gave the nVidia product an advantage of £40-£50 in pricing. Which leaves the Sapphire Radeon HD 6850.
At the time of writing, the Sapphire Radeon HD 6850 was available in large numbers for around £160, although some outlets were advertising it at £145-£150. We'll take £160 as the reference price, and if you can get this for £150 or less, then this card looks even better value.
As the Sapphire Radeon HD 6850's price suggests, this graphics card is very much a cut-down version of the 6870. In many respects, it retains much of what made the 6870 so impressive, though. And it's even more discreet, needing just one 6-pin power connector and with a thermal design power (TDP) listed at a modest - for a graphics card anyway - 127W.
This 1.7 billion transistor chip comes, like the 6870, with a full 256bit memory interface. Inevitably, though, a good number of the specifications have been cut down. The 1120 stream processors have been cut to 960 in the case of the 6850. Given that the nVidia cards make do with considerably fewer stream processors (even the GTX 470 has less than half the number of the 6850, while the 460 has little more than a third), this is clearly little handicap to the Sapphire Radeon HD 6850.
The 6870's 52 texture units have been shaved slightly to 48, although the number of raster operations remains the same, at 32.
Sapphire Radeon HD 6850: Speed and performance
This early Sapphire version of the 6850 sticks very much to the factory settings (although an enhanced Toxic version should also be out as you read this), so you get 775MHz core and 1,000MHz (an effective 4,000MHz, taking into account the GDDR5 RAM) memory clock speeds. Compare that to the 6870's respective figures of 900MHz and 1,050MHZ (4,200MHz effective).
There's obviously a significant difference here, particularly when it comes to the core clock, and the Sapphire Radeon HD 6850's fill rates are noticeably down - 37.2GTps rather than the 6870's 50.4GTps. The Sapphire Radeon HD 6850 is still competitive with the GTX 460, though, falling just behind the 37.8GTps notched up by the 1GB version of that chip. The 6850 is closer to its big brother in terms of memory bandwidth, since both chips share a 256-bit memory interface. The 6850's score of 128GBps is only a short way behind the 6870's 134.4GBps - and a long way clear of the GTX 460's 115.2GBps.
You need to add to this the excellent new features of ATI's new Barts architecture. The Sapphire Radeon HD 6850 has significantly advanced tessellation over previous ATI cards, and the Eyefinity multi-screen feature has been stretched out. Indeed, this 6850 comes with two DVI ports, and HDMI and DisplayPort connectors. We'll be excited to see how ATI's new three-dimensional HD3D facilities fare.
In terms of performance, the Sapphire Radeon HD 6850 falls only a short way behind the 6870. More crucially though, it beats the similarly priced GTX 460 in every test. The difference is rarely more than a couple of frames.
In Crysis, for example, the Sapphire Radeon HD 6850 notches up 27.8 and 22.9 frames per second at the 1680x1050 and 1900x1200 resolutions. This places it between 0.4 and 0.8fps ahead of the GTX 460, and 0.9-1.1fps behind the 6870.
At 1280x720, it beats the GTX 460 by over two frames. In the Heaven benchmark, its figures of 27.6 and 23.8fps at the higher resolutions place it 0.9-1.3fps behind the 6870 and 1-1.3fps ahead of the GTX 460.
In Stalker: Call of Pripyat, it finishes 0.7-0.9fps behind the 6870, and the same amount ahead of the GTX 460.
Next page: Our expert verdict >>
And for another look at the 6850, this time an AMD model: AMD Radeon HD 6850 review